Authorities in Estonia have ordered a ship linked to a toxic waste dumping scandal in Ivory Coast to remain in port while they conduct a criminal investigation.

Estonian prosecutors announced the criminal probe Wednesday after test results showed trace amounts of the same chemicals that the ship unloaded in Ivory Coast.

It says the Panamanian-registered ship, the Probo Koala, will remain at the port of Padilski while the investigation continues.

Chemicals from the ship that were illegally dumped in Abidjan last month are blamed for the deaths of at least eight people. Thousands of others were made sick by poisonous fumes from the waste.

The Estonian prosecutor's office says its tests showed the chemicals to be toxic. The Dutch-based company that owns the ship, Trafigura, says its own tests found the chemicals to have little or no toxicity.

The environmental group Greenpeace has blockaded the ship in Estonia for several days while urging local authorities to investigate.